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In addition work is in progress to install: BUITMS in Quetta, Bolochistan; Sindh Agriculture University Tandojam in Karachi, Sindh; NCEMB University in Lahore, Punjab; Virtual University in Lahore, Punjab; Air University in Islamabad, Federal Territory; Kinnaired College for Women in Lahore, Punjab.
The growth in the number of monitors and host pairs being monitored over 2010, is seen below (spreadsheet ):
Map of sites
The locations of the Pakistani monitoring (red) and remote(red and blue) hosts are seen in the PingER maps below.
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Using PingER, the monitoring hosts ping each remote host with 10 pings every 30 minutes. From this data we are able to measure minimum and average Round Trip Times (RTT), jitter, loss, unreachabilty (all 10 pings fail) and derive throughput and Mean Opinion Score (MOS). The data is gathered from the monitoring sites on a daily basis by the archiving sites at NUST, SLAC and FNAL.
Results
Unreachability
A host is considered unreachable if none of the pings sent to it are responded to. To illustrate this we chose a reliable host at SLAC (pinger.slac.stanford.edu) and analyzed the unreachability of Pakistani hosts seen from SLAC.
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Table of unreachability seen from SLAC to Pakistani hosts in 2010. Higher values (bad) are colored redder. The data is sorted by increasing unreachability in Jan 2011. Spreadsheet | Chart of the unreachability of Pakistani hosts seen from SLAC Dec 2010 and Jan 2011 | Smokeping examples of unreachabillty seen from SLAC for 120 days Oct 2010 - Jan 2011. |
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If we select the same host-pairs in both say Nov 2010 and April 2010 then the improvement ((ipdv(Apr)-ipdv(Nnov))/ipdv(Apr) in IPDV is about 47%. Thus things have improved with lower IPDVs for the selected host pairs, or in other words the improvement is not just that more recntly added hosts had lower IPDVs.
Throughput
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(for more information on how throughput is derived please click here).
We derive the throughput from the loss and RTT measurements as throughput = 1460*8[bitsWiki Markup
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Median derived throughput (blue line) with the 25% and 75% seen from SLAC to hosts in Pakistan from Dec 2003 - Dec 2010. The number of hosts being monitored in Pakistan is seen in the brown line. Spreadsheet | Derived throughput between Pakistani region in 2010. Spreadsheet |
The derived throughput seen from SLAC in the graph on the left, has increased by roughly a factor of 2 in 5 years. Within Pakistan (graph on the right) the throughput to Quetta is the poorest, followed by Karachi. Since most monitoring hosts are in the North of Pakistan, in particular in Islamabad, there are mainly long RTTs to Karachi and Quetta and hence low throughput (since throughput goes as 1/RTT).
Mean Opinion Score (MOS)
The telecommunications industry uses the Mean Opinion Score (MOS) as a voice quality metric. The values of the MOS are: 1= bad; 2=poor; 3=fair; 4=good; 5=excellent. A typical range for Voice over IP is 3.5 to 4.2 (see VoIPtroubleshooter.com). In reality, even a perfect connection is impacted by the compression algorithms of the codec, so the highest score most codecs can achieve is in the 4.2 to 4.4 range. Using the RTT, loss and jitter we derive the MOS.
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Median MOS and Inter Quartile Range (IQR) between Pakistani hosts for 2010. Spreadsheet. | MOS between Pakistani regions | MOS for fixed set of Pakistani hosts by region |
It is apparent that the MOS is very variable, and according to the middle graph above appears to be decreasing (getting worse) in time (see left hand and middle graphs). Some of this decrease is due to bringing on new hosts that have poorer MOS performance. If we fix on just aggregating the performance for hosts pairs that have been monitored for the whole period we get the graph on the right. This set of hosts consists of: PK.NEDUET.EDU.N1, PK.COMSATS.EDU.N2, PK.NCP.EDU.N3, PK.NIIT.EDU.N2, PK.NIIT.EDU.N7, PK.AUP.EDU.N2, PK.PERN.EDU.N1, PK.UET.EDU.N2 and PK.LSE.EDU.N3. In any case the MOS is well above the threshold of 3.5 mentioned above, so VoIP calls within Pakistan between these hosts should be successful.
Alpha
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The speed of light in fibre is roughly _0.66*c_ (where c is the speed of light in vacuum). Using 300,000km/s as c this yields Round Trip Distance = _RTD\[km\]=100\[km/msec\]*minimum_RTT\[msec\]_ as a way to derive the distance between the two hosts making the minimum RTT measurement. This assume the minimum RTT is only affected by the transmission of light in the fibre (i.e. no delays due to network devices such as routers) and that the fibre route is direct (a great circle route) between the two hosts. The use of minimum RTT is meant to eliminate most network device delays for reasonable fast circuits (e.g. at 100Mbits/s assuming no queuing the router delays is ~ 0.12msec). To To accomodate these extra delays one introduces a function alpha, so that _RTD\so that RTD[km\]=alpha*100\[km/msec\]*minimum_RTT\[msec\]._ Large values of alpha close to one indicate a direct path, and small values usually indicate a very indirect path. This assumes no queuing and minimal network device delays. The chart below shows the alpha values between regions in Pakistan. It is based on the minimum RTTs seen between Dec 2009 and Nov 2010.
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Average Alpha measured between regions of Pakistan with the standard deviations (as error bars) and the number of host pairs contributing to the measurement. Spreadsheet |
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